Luisa's BRC task notes

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Here is where I will put the answers as I do it. Don't peek until you've tried yourself!

Data from other wavelengths

(13 May 2011)

Coordinates I used:

  • BRC 27 : 07:04:00 -11:22:55
  • BRC 34 : 21:33:30 +58:04:32

This is all I found. I only used Skyview for POSS; the rest comes from IRSA:

bands          BRC 27         BRC 34
spitzer         yes           yes
wise img        yes           not yet
wise catalog    yes           not yet
iphas           no            yes!
sdss            no            no
akari irc	 yes           yes          
2mass catalog   yes (psc/xsc) yes (psc/xsc) 
msx images      no?           yes (but nothing there!)
msx catalog     yes           yes
denis catalog   yes           no
planck catalog  yes           yes
usno            yes           yes
poss            yes           yes

(end 13 May 2011)

Previously-identified sources

(24 June 2011) -- copied out of email.

BRC 34, ogura source 2, or what to do if you can't find a counterpart by searching in the 2mass catalog.

1) go get the finder chart view of it. sure enough, there's nothing screamingly obvious at this location. see attached.

2) go double-check that you've copied the coordinates correctly from the paper. you have: 21 33 55.8 +58 01 18 and that's what i see in the paper too. so that's right.

3) check to see if there is a finder chart of any sort in the paper. yep, figure 1-o, on the 17th page of the article. unfortunately, obj 2 is kind of in the corner, so we only have a little bit of surrounding sky to compare. now, it gets challenging. go back to finder chart, and ask for a larger patch of sky. the largest it will give you is only 6 arcmin, but the caption for fig 1 claims that the images here are 4.2' by 6' wide, so that *should* be enough. now you have to look for the same stars in both frames. this is not trivially obvious to me right now -- sometimes it is, but not here. i tried the position given for source 1 too, to get a sense of scale. it doesn't actually say in the paepr, but i think those images are Ha, so it's somewhat hard to compare the nebulosity with that from POSS or 2mass, and stars that are bright in one might not be in the other, so i was hoping that source 1 would help us get oriented, given the bright star to its west (left) in the image in the paper. that one i can find (and orient in the image). look at how different the stars look in POSS and 2mass, and how faint the target is in POSS. then i went back to source 2, and could then identify where it is supposed to be. if i get the full-res J image, i can see a smudge right at that position. SO, here is how i interpret this:

  • stars vary, especially young stars. this guy probably flared in Ha (e.g., ate something out of its disk) right when ogura looked at it, but not necessarily when 2MASS did.
  • the coordinate from ogura lines right up with a faint smudge in the 2mass image, so the coordinates are probably ok (as they appear in ogura) for matching to IRAC, but we will have to keep that in mind when we look for a counterpart, because the correct IRAC source match may be more than 1 arcsec away from this position.
  • we need to make a note of all of this, becuase if this eventually turns into a paper, all of this is important to describe in the paper. the fact that it appears to likely be variable is a GOOD thing, because variability is one of the characteristics of young stars.
  • also, this source is kinda far away from the 'center' of BRC 34, so i was worried it was off the edge of our maps. it's on the edge (across a gap actually), but i see it. however, we only have data for it in 2 channels. better than nothing, but as a result, we would not have picked it out as a YSO candidate without this literature identification.

(end 24 June 2011)